Disposable syringes are in widespread use for a number of different types of applications. For example, syringes are used not only to withdraw a fluid (e.g., blood) from a patient but also to administer a medication to a patient. In the latter, a cap or the like is removed from the syringe and a unit dose of the medication is carefully measured and then injected or otherwise disposed within the syringe.
As technology advances, more and more sophisticated, automated systems are being developed for preparing and delivering medications by integrating a number of different stations, with one or more specific tasks being performed at each station. For example, one type of exemplary automated system operates as a syringe filling apparatus that receives user inputted information, such as the type of medication, the volume of the medication and any mixing instructions, etc. The system then uses this inputted information to disperse the correct medication into the syringe up to the inputted volume.
In some instances, the medication that is to be delivered to the patient includes more than one pharmaceutical substance. For example, the medication can be a mixture of several components, such as several pharmaceutical substances.
By automating the medication preparation process, increased production and efficiency are achieved. This results in reduced production costs and also permits the system to operate over any time period of a given day with only limited operator intervention for manual inspection to ensure proper operation is being achieved. Such a system finds particular utility in settings, such as large hospitals, including a large number of doses of medications that must be prepared daily. Traditionally, these doses have been prepared manually in what is an exacting but tedious responsibility for a highly skilled staff. In order to be valuable, automated systems must maintain the exacting standards set by medical regulatory organizations, while at the same time simplifying the overall process and reducing the time necessary for preparing the medications.
Because syringes are used often as the carrier means for transporting and delivering the medication to the patient, it is advantageous for these automated systems to be tailored to accept syringes. However, the previous methods of dispersing the medication from the vial and into the syringe were very time consuming and labor intensive. More specifically, medications and the like are typically stored in a vial that is sealed with a safety cap or the like. In conventional medication preparation, a trained person retrieves the correct vial from a storage cabinet or the like, confirms the contents and then removes the safety cap manually. This is typically done by simply popping the safety cap off with one's hands. Once the safety cap is removed, the trained person inspects the integrity of the membrane and cleans the membrane. An instrument, e.g., a needle, is then used to pierce the membrane and withdraw the medication contained in the vial. The withdrawn medication is then placed into a syringe to permit subsequent administration of the medication from the syringe.
FIG. 1 illustrates an exemplary conventional syringe 10 that includes a barrel 20 having an elongated body 22 that defines a chamber 30 that receives and holds a medication that is disposed at a later time. The barrel 20 has an open proximal end 24 with a flange 25 being formed thereat and it also includes an opposing distal end 26 that has a barrel tip 28 that has a passageway 29 formed therethrough. One end of the passageway 29 opens into the chamber 30 to provide communication between the barrel tip 28 and the chamber 30 and the opposing end of the passageway 29 is open to permit the medication to be dispensed through a cannula (not shown) or the like that is later coupled to the barrel tip 28.
An outer surface of the barrel tip or luer 28 can include features to permit fastening with a cap or other type of enclosing member. For example, the luer can have threads 27 that permit a tip cap 40 to be securely and removably coupled to the barrel tip 28. The tip cap 40 thus has complementary fastening features that permit it to be securely coupled to the barrel tip or luer 28. The tip cap 40 is constructed so that it closes off the passageway 29 to permit the syringe 10 to be stored and/or transported with a predetermined amount of medication disposed within the chamber 30. As previously mentioned, the term “medication” refers to a medicinal preparation for administration to a patient and most often, the medication is contained within the chamber 30 in a liquid state even though the medication initially may have been in a solid state, which was processed into a liquid state.
The syringe 10 further includes a plunger 50 that is removably and adjustably disposed within the barrel 20. More specifically, the plunger 50 is also an elongated member that has a proximal end 52 that terminates in a flange 54 to permit a user to easily grip and manipulate the plunger 50 within the barrel 20. Preferably, the plunger flange 54 is slightly smaller than the barrel flange 25 so that the user can place several fingers around, against, or near the barrel flange 25 to hold the barrel 20 and then use fingers of the other hand to withdraw or push the plunger 50 forward within the barrel 20. An opposite distal end 56 of the plunger 50 terminates in a stopper 59 or the like that seals against the inner surface of the barrel 20 within the chamber 30. The plunger 50 can draw a fluid (e.g., air or a liquid) into the chamber 30 by withdrawing the plunger 50 from an initial position where the stopper 59 is near or at the barrel tip or luer 28 to a position where the stopper 59 is near the proximal end 24 of the barrel 20. Conversely, the plunger 50 can be used to expel or dispense medication by first withdrawing the plunger 50 to a predetermined location, filling the chamber 30 with medication and then applying force against the flange 54 so as to move the plunger 50 forward within the chamber 30, resulting in a decrease in the volume of the chamber 30 and therefore causing the medication to be forced into and out of the barrel tip or luer 28.
Typically, a drug is provided of the shelf in solid form within an injectable drug vial that is initially stored in a drug cabinet or the like. To prepare an injectable unit dose of medication, a prescribed amount of diluent (water or some other liquid) is added to the vial to cause the solid drug to go completely into solution. Mixing and agitation of the vial contents is usually required. This can be a time consuming and labor intensive operation since first it must be determined how much diluent to add to achieve the desired concentration of medication and then this precise amount needs to be added and then the vial contents need to be mixed for a predetermined time period to ensure that all of the solid goes into solution. Thus, there is room for human error in that the incorrect amount of diluent may be added, thereby producing medication that has a concentration that is higher or lower than it should be. This can potentially place the patient at risk and furthermore, the reconstitution process can be very labor intensive since it can entail preparing a considerable number of medication syringes that all can have different medication formulations. This also can lead to confusion and possibly human error.
What is needed in the art and has heretofore not been available is a system and method for automating the medication preparation process and more specifically, an automated apparatus for reconstituting and then delivering a prescribed amount of medication to a syringe or the like.